Exponential Decay Questions and Answers

Get help with your Exponential decay homework. Access the answers to hundreds of Exponential decay questions that are explained in a way that's easy for you to understand. Can't find the question you're looking for? Go ahead and submit it to our experts to be answered.

Get help with your Exponential decay homework.

Try it risk-free

Radioactive decay is a process that follows first-order kinetics. The half-life of ^{32} P is 0.03920 years; How long (in minutes) would it take for the amount of ^{32} P to decrease to 53.25 % of its

26. The number of U.S. citizens aged 65 years and older from 1900 through 2050 is estimated to be growing at the rate of R(t) = 0.063t -0.48t + 3.87 { (0\leq t \leq 15) } million people/decade, wh

The speed of a falling skydiver is v(t) = 58 (1 - e^-t/3) in metres per second, where t is the number of seconds since leaving the plane. Then the terminal velocity is The difference |v(t) - L| can be

In theory, drugs that decay exponentially always leave a residue in the body. However, in practice, once the drug has been in the body for 5 half-lives, it is regarded as being eliminated. If a patien

A used car has a value of $15,250 when it is purchased in 2012. The value of the car decreases at a rate of 7.5% per year. a) Write an exponential function that models the value of the car, y, over x

Suppose a beam of X-rays whose intensity is A rads (the "rad" is a unit of radiation) falls perpendicularly on a heavy concrete wall. After the rays have penetrated s feet of the wall, the radiation i

Consider the following exponential probability density function. f(x) = 1/4 e^{-3/4} for x greater than or equal to 0 a. Which of the following is the formula for P(x less than or equa

Consider a drug that is taken in 50 mg doses daily. Suppose that the first dose is taken when t=0 and that t is measured in hours. a. If the half-life of the drug is 7 hours, what fraction of t

Consider a drug that is taken in 55 mg doses daily. Suppose that the first dose is taken when t = 0 and that t is measured in hours. a. If the half-life of the drug is 6.6 hours, what fraction of the

The probability density function of the time to failure of an electronic component in a copier (in hours) is f(x) = (e^{-x}/1076)/(1076) for x is greater than 0. Determine the probability that A) A

Calcium-47 is a Beta-emitter with a half-life of 4.50 days. If a bone sample contains 2.04 g of this isotope, at what rate will it decay?

The half-life of ^{222} Rn_{86} is 3.8 days. What is its decay constant?

A 0.9 ml dose of a drug is injected into a patient steadily for half a second. At the end of this time, the quantity, Q, of the drug in the body starts to decay exponentially at a continuous rate of 0

Write the rates for the following reactions in terms of the disappearance of reactants and appearance of products. a. 3O2 arrow 2O3 b. C2H6 arrow c2H4 + H2 c. ClO- + Br- arrow BrO- + Cl- d. (CH3)3CCl

Devise an exponential decay function that fits the given data, then answer the accompanying question. Be sure to identify the reference point (t = 0) and units of time.

If a new truck costs $43,750 and it depreciates 18 percentage per year, what will the truck be worth in 5 years?

A turkey is removed from an oven on thaksgiving at 6:25 PM.At this time it is 225^{\circ} F.It is placed on the table in the living room and left to cool. At 6:40 PM, the turkey cools to 175^{\circ}

Using the curve for the decomposition of Carbon 14, find the age of a prehistoric cave painting discovered in the Lascaux Caves in southern France if the amount of Carbon 14 has decayed to 14.29%.

Suppose that a population is dying with a half life of 43 years. The initial size is 1600. Find the 1 year DTDS for this population.

Question 3 of 29 Incorrect Incorrect Sapling Learning Determine the average rate of change of B from t = 0 s to t = 302 s. A --> 2B |Time (s) |Concentration of A (M) |0 | 0.620 |151

A fragment of bone is discovered to contain 20% of the usual carbon-14 concentration. Estimate the age of the bone to the nearest hundred years, given that Carbon-1 is radioactive with half-life of 5

It is a dark clear night. The air temperature is 15^o C. A body is discovered at midnight. Its temperature is 23^o C. One hour later, the body has cooled to 20^o C. Use Newton's law of cooling to dete

A container of hot liquid is placed in a freezer that is kept at a constant temperature of 10 degrees F. The initial temperature of the liquid is 160 degrees F. After 5 minutes, the liquid's temperatu

An unknown amount of a radioactive substance is being studied. After two days, the mass is 15 grams. After eight days, the mass is 9 grams. Assume exponential decay. How much of the substance was ther

In November 2010, a tiger summit was held in St. Petersburg, Russia. In 1900, there were 100,000 wild tigers worldwide; in 2010 the number was 3200. (a) Assuming the tiger population has decreased e

1. A botanist conjectures that the height of a certain type of pine tree can be modeled by a learning curve. To test his conjecture, he plants a 2-foot tall tree. He knows that eventually, the tree wi

A standard cup of coffee contains about 100 mg of caffeine, and caffeine leaves the body at a rate of 17% per hour. Give formulas for the amount of caffeine in the body after t if the 17% rate is (a)

When a hot object is placed in a water bath whose temperature is 25^\circ C, it cools from 100^\circ C to 50^\circ C in 200 s. In another bath, the same cooling occurs in 180 s. Find the temperature o

If a train going at a steady pace traveled 40 miles in half an hour, what is the train's constant rate?

Suppose that in any given year, the population of a certain endangered species is reduce by 25%. If the population is now 7500, in how many years will the population be 4000?

Suppose the amount of oil pumped from one of the canyon wells in Whittier, California decreases at a continuous rate of 10% per year. When will the well's output fall to 80% of its present value?

One of the main contaminants of a nuclear accident, such as that at Chernobyl, is strontium-90, which decays exponentially at a continuously compounding rate of approximately 2.4% per year. (a) Write

When the Olympic Games were held outside Mexico City in 1968,there was much discussion about the effect the high altitude (7340 feet) would have on the athletes.Assuming air pressure decays exponentia

An air-freshener starts with 30 grams and evaporates. In each of the following cases, write a formula for the quantity, Q grams, of air-freshener remaining t days after the start and sketch a graph of

Coroners estimate time of death using the rule of thumb that a body cools about 2 degrees F during the first hour after death and about 1 degree F for each additional hour. Assuming an air temperatur

Skeletal remains had lost 81% of the C-14 they originally contained. Determine the approximate age of the bones. (Assume the half life of carbon-14 is 5730 years. Round your answer to the nearest whol

A wooden artifact recovered from a tomb contains 29% of the carbon-14 that is present in living trees. The half life of carbon-14 is 5730 years. How long ago was the artifact made?

Santr 109 (a fictitious substance) decays by about 6% every day. How much of an 84-pound sample remains after: (a) 7 days (b) 3 weeks (b) 48 days.

A truck depreciates in value by 15% per year. If the truck is valued at $ 40 000 on August 1, 2010, what will its value be to the nearest dollar on August 1st 2016?

If a bone is found to have 20% of its normal amount of carbon 14, how old is the bone?

A roast turkey is taken from an oven when its temperature has reached 185 degree F and is placed on a table in a room where the temperature is 75 degree F. Assume Newton's Law of Cooling: An object co

Suppose the decay equation for a radioactive element is known to be y = y_o e^{-0.25t}, with t in years. About how long will it take for the sample of this element to decay to 70% of its original amou

Radioactive substances decay at a rate proportional to the amount, i.e. dN/dt=-kN with k a positive constant. Uranium-238 has a half-life of 4.5 x10^9 years. How long will it take 500 grains of Urani

An object is immersed in a medium kept at a constant temperature of 100. After one unit of time, the temperature of the object is 10. After another unit of time, the temp of the object is 15. The obje

An unknown radioactive element decays into non-radioactive substances. In 420 days the radioactivity of a sample decreases by 39 percent. 1.What is the half-life of the element? 2.How long will it t

An unknown radioactive element decays into non-radioactive substances. In 580 days the radioactivity of a sample decreases by 45 percent. (a) What is the half-life of the element? half-life: (days)

A scientist puts 150 grams of radioactive radium having a half-life of 1690 years into a concrete vault. What will be the average amount of radium in the vault during the next 1300 years? (Round inter

The half-life of plutonium-241 is approximately 13 years. a) How much of a sample weighing 8 g will remain after 110 years? b) How much time is necessary for a sample weighing 8 g to decay 0.1 g?

A cup of coffee contains 99 mg of caffeine, which leaves the body at a continuous rate of 16% per hour. (a) Write a formula for the amount, mg, of caffeine, in the body , hours after drinking a cup o

The half-life of plutonium-241 is approximately 13 years. a)How much of a sample weighing 4 g will remain after 90 years? b)How much time is necessary for a sample weighing 4 g to decay 0.1 g? A) A

The half-life of plutonium-241 is approximately 13 years. a)How much of a sample weighing 8 g will remain after 90 years? b)How much time is necessary for a sample weighing 4 g to decay 0.1 g? A) Af

Poli 761 (a fictitious substance) decays by about 7% every day. How much of a 88 pound sample remains after 9 days?

The half-life of cesium-137 is 30 years. Suppose we have a 180-mg sample. \\ (a) Find the mass that remains after t years. \\ (b) How much of the sample remains after 120 years? (Round your answer to

The half-life of radioactive strontium-90 is approximately 29 years. In 1965, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons and was absorbed into people's

Warfarin is a drug used as an anticoagulant. After administration of the drug is stopped, the quantity remaining in a patient's body decreases at a rate proportional to the quantity remaining. Suppos

A sample of a radioactive substance decayed to 94.5 \% of its original amount after a year. (Round your answers to two decimal places.) (a) What is the half-life of the substance? (b) How long woul

A painting attributed to Vermeer (1632-1675), which should contain no more than 96.2\% of its original carbon-14, contains 99.1\% instead. Using the fact that Carbon-14 has half-life of 5730 years, de

Atmospheric pressure decays exponentially as altitude increases. With pressure, P, in inches of mercury and altitude, h, in feet above sea level, we have (a) At what altitude is the atmospheric pressu

One of the main contaminants of a nuclear accident, such as that at Chernobyl, is strontium-90, which decays exponentially at a continuously compounding rate of approximately 2.3% per year. (a) Write

The half-life of radioactive strontium-90 is 29 years. In 1960, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people s bones. How m

Support